Vapor generator



Jan. 16, 1945. J, R 2,367,193

VAPOR GENERATOR Filed NOV. 4 1941 INVENTOR Jaw/v 52 z/7& D

ATTORNEY 4 the invention, and

Patented Jan. 16, 1945 1 .2361193 VAPOR GENERATOR John Blizard, garden city,- N. Y., assig'nor to Foster Wheeler Corporation, New York, N. Y., a corporationof New York Y Application November 4, 1941, SerialNo. 417,754 SQlaims. (c1. 122-479) This invention relates'to vapor generators and particularly pertains to a method of, andapparatus for, controlling the degree of superheat of vapors in vapor generators.

The invention provides a method of,jand for, readily and easily regulating .the degreeof superheat of the vapor to meet different operating requirements, or for maintaining the degree of superheat constant over a wide range of generator loads or ratings.-

In accordance with the invention, asteam generator, for example,.is arranged so that the superheater and the burners for firing the iurnace thereof are so positioned relative to each other that the superheater will receive a greater amount of-radiant heat'from the firing of one burner or group of burners than it will receive from the firing of another burner or group of burners. This is accomplished by placing the superheater in a recess in the furnacewall so that it is shielded more or less from the radiant heat of certain burners, but is exposed to direct radiation from the flamesof other burners, or the'superhe'ater elements may be inclined at such an angle as to receive a greater amount'of radiant ,heatfrom some burners than from others. Additionally,

' refractory material may be placed on certain of means disposed infront wall M of the setting, to'direct a stream of gases of combustion toward the rear of the chamber. The groups of burners l2 and 13 are vertically spaced from each other, and the burners of each group are horizontally spaced.

- The furnace chamber is provided with a hopper bottom formed by oppositely inclined side wall portions l5 and it. The upper portion of the furnace chamber is defined by vertical side walls I! and I8., Between the lower end of the side walls and the upper end of the hopper walls are clined oppositely to the hopper Walls I5 and I6 wall portions [9 and which are vertically inrespectively. In the upper portion of the setting are upper steam and water drums 2| and 22.. The drum 2| is connected to a lower drum 23 by a vertical bank of steam generating tubes 24, and the drum 22 is connected to the lower drum 23 by a vertically inclined bank of tubes 21 which extend transversely of the chamber ll. Gases flow from the settingthrough a flue passage 26.

Extending between the two upper drums are horizontal groups 28 and 29 of-circulator tubes. Disposed in the space bounded by the group of circulator tubes 29, vertically inclined bank 21 and vertical bank 24, is a convection superheater the heat absorbing elements of the generator in such a manner that the radiant heat received directly by the superheater from the flames of certain burners will be augmented by the re-radia-.

tion to the superheater of heat received by this refractory material from the burners.

With these arrangements, the temperature to which the steam is superheated may be controlled by differentially firing the burners or burner groups, or by increasing the supply of fuel to certain burners and decreasing it to other burners,

or the temperature of the steam may be regulated Iii! which is in the path of the gases flowing from the furnace to the flue passage 26. Saturated steamis conducted from drum 2! through line 3! to the superheater inlet header 32 and after flowing-through the superheater, it is conducted from the outlet header 33 by a line 3 5.

The inner surfaces of the furnace walls l1 and it are lined respectively with water wall tubes 35 Fig. 1 is ,a more or less diagrammatic vertical sectional view of a steam generator embodying r Fig. 2 is a partial vertical sectional view of one .of the furnace walls showing one means for increasing the radiant heat to a superheater. ..Referring to the drawing, th steam generator illustrated comprises a setting I0 having a fur- -na'ce chamber H fired by fuel burners IZ- andl3' and 36. At their upper ends the Water wall tubes 35 are connected to the drum 23 and at their lower ends to a header 3'1. The water wall tubes 36- are connected at their upper ends to the drum 22 and at their lower ends to a header 38. These tubes are connected with the circulatory system of the unit in any desired manner. The inner surface of the walls [5 and it of the hopper'bottom are lined respectively with water wall tubes 39 and 49. The water wall tubes 39 are connected at their lower ends to a header 4! and at their upper ends to a header 42, while the tubes 40 are conne'cetd at their upper'ends to a'header t3 and' at their lower ends to a header 44. The tubes 39 and 40 are connected to the circulatory system of the generator by suitable downcorner connections, not shown, in any desirable manner so that they will be cooled by the circulation of water therethrough. The tubes 39 and ti] may also be used as superheaters in which event they would be connectedas hereinafter described. a

terial is capable of radiating heat.

Lining the inner surfaces of the furnace wall portions I9 and 20 are radiant heat absorbing superheater tubes 46 and 41 respectively. The tubes 46 are connected to inlet and outlet headers 48 and 49 respectively, while the tubes 41 are connected to inlet and outlet headers 50 and SI. As shown, saturated steam passes from the drum 2I through the conduit 3I to the convection superheater 36. From the, convection superheater-the steam may be passed to either the superheater 46 or the superheater 41. For example, the steam may be passed from the convection superheater 30 through the line 34 to the radiant superheater 41 through the inlet header 50 thence from the outlet header I to the inlet header 48- for the radiant heat absorbing superheater tubes 46 so.

that the final temperature of the superheated steam will be a result of the combined heating effect of both the convection and the radiant superheaters. superheater 30 could be passed into the radiant superheater 46 thence into the radiant superheater 41. With the arrangement of the present invention, the superheater tubes 46 and 41 are directly exposed to radiant heat from the fuel burners I2 but substantially shielded from direct radiations from the flames produced by the burners I3.

In operation, gases of combustion fiow'from the furnace chamber II over the bank of tubes 21, the convection superheater 30v and the bank of steam generating tubes 24 into the flue passage 26. Steam from the drum 2| is conducted to and through the convection superheater and then flows to and through the radiant superheaters 41 and 46. If a high degree of superheat is required, the burners I2 and Bare operated. The superheater tubes 46 and 41 are exposed directly to the radiant heat of the flame from the burners I-2, but due to their position in the setting, are only indirectly exposed to the radiant heat of the flame from burners I3.

If a low degree of superheat is required, burners I3 only are operated, or, one or more -of these burners are operated, depending upon the degree of superheat required. When these burners only are used, the superheater tubes 46 and 41 are only indirectly exposed to the radiant heat of these burners, in consequence of which. the steam flowing therethrough is not heated to as high a degree as-When the burners I2 are operated.

It will be perceived therefore that the intensity of firing of the different burners. or burner groups, or the number of burners of each group in operation, may be varied to obtain any desired degree of superheat at any load onthe-generator. The ratio of air and fuel supplied to the various burners also may be adjusted to regulate thetemperature of the steam. In the form shown, however, tubes 46 and 41 will receive a higher degree of heat under Various firing conditions from. the burners I2 than from the burners I3.

In the embodiment of the invention shown in Fig. 2, at least part ofthe tubes 39 and 40. are covered. with refractory material 45,whichma- When the tubes 39 and 4-0, or a part thereof,v are covered with a refractory material, heat from the-burners I2 and I3 is re-radiated from the m'aterialto the tubes 46 and 41, thereby increasing the radiant heat received by these tubes. Due to the proximity of the burners I2 to thezrefractory surfaces,

Obviously, steam from the convection the maximum quantity of heat will be re-radiated 1;

from these surfaces to the tubes 46 and 41 when the burners I2 are operated.

Although the invention is disclosed as embodied in a vapor generator having a combination convection and radiant superheater, it is also appli-- cable to any vapor generator having a single superheater so disposed in the furnace chamber that in operation it will be more directly exposed to radiations from one'burner or groupzof burners than from the radiations of another burner or group of burners. It is obvious that the convection superheater 30 may be omitted and one or both of the radiant superheaters only may be utilized. Obviously, the manner of connection of thesuperheaters to one another is a matter of choice.

If desired, the water wall tubes 39 and 46 on theinner surface'of the walls I5 and I6 respectively of the hopper bottom may be replaced by superheater tubes. 'When superheater tubes are so used, the'steam preferably is passed from the steam drum 2| or from'the convection superheater, serially through the tubes 40, 41, 39 and 46, so that the final temperature of the superheated steam will be dependent upon the combined heating effect of these tubes.

Although a preferred embodiment of the invention is disclosed herein, changes may be made in the particular form and relative arrangement of the various parts of the apparatusdescribed without departing from the principles of the invention which is not to be limited excepting by the scope of the appended claims.

What is claimed is:

'1. A vapor generator comprising a setting having opposite side and end walls, vapor generating tubes in the setting, a furnace chamber within said Walls and having portions offset therefrom in opposite side walls thereof, said ofiset portions each having a vertically inclined wall, a radiant superheater in each of said offset portions adjacent and substantially parallel to the inclined wall thereof, means for firing said furnace comprising burners'in one end Wall of said setting adapted to direct a stream of gases of combustion toward the other end Wall, at least one of said burners being. so. disposed that heat from the gases of combustion: thereof is radiated directly into thev offset portions, and another burner so positioned that the radiant superheaters. are substantially shielded from radiations from the gases of combustion thereof.

'2. A steam generator comprising a setting havingopposite-side andLend walls, steam generating tubes in. the setting, a furnace chamber Within said walls, a hopper bottom associated with the furnace comprising opposite walls inclined inwardly, side wall portions inclined oppositely to said hopper bottom-walls and extending between the upper portion of the hopper bottom walls and the lower portion of thefirst-mentioned side walls, radiant superheaters extending along the opposite hopper Walls and the said side wall portions, separately controlled burner-s in one end wall of the setting adapted to direct a stream of gases of combustion toward the oppositeend wall, at. least oneof said burners being so disposed that heat from the gases of combustion thereof is radiated directly to the radiant superheaters, and another burner. so positioned that the radiant heatzsuperheaters are substantially shielded from radiations, from the gases of. combustion thereof.

3. A- steamgeneratorcomprising asetting having opposite-side and end walls, steam generating tubes in-thesetting, a furnace chamber with- "in said walls, a water cooled hopper bottom associated with the furnace comprising opposite walls inclined inwardly, refractory material covering at least a part of. said walls, side wall portions inclined oppositely to said hopper bottom walls and extending between the upper portion of the hopper bottom walls and the lower portion of the first-mentioned side Walls, radiant superheaters extending along they said side wall portions, separately controlled burners in one end wall of the setting adapted to direct a stream of gases of combustion toward the opposite end wall, at least one of said burners being so disposed that heat from the gases of combustion thereof is radiated directly to the radiant superheaters, and another burner so positioned that 4. A steam generator comprising a setting having opposite side and end walls, a furnace chamber within said walls having a portion offset therefrom in the lower portion thereof, upper steam and water drums positioned at opposite sides of said chamber} at the upper end thereof, a lower drum, a substantially vertical bank of steam generator tubes between the lower drum and one of the upper drums, a vertically inclined bank of tubesextending from the lower drum transversely of the chamber to the other upper drum, tubes extending between the two upper drums, a flue passage through which gases of combustion pass after flowing through said vertical bani; of tubes, a radiant superheater in the offset portion of said furnace adapted to rechamber having a gas outlet adjacent the upper portion thereof, said chamber having a laterally offset portion therein with a vertically inclined wall, a radiant superheater in said offset portion adjacent and substantially parallel to the inclined wall thereof, a burner for firing the furnace chamber so disposed that heat from the gases of combustion thereof is radiated directly into the offset portion, and another burner positioned at a higher elevation than the first mentioned burner and at a lower elevation than said outlet,

said other burner being disposed to fire in such a direction that the gases in flowing to the outlet will not descend a substantial distance below the burner and so that the radiant superheater will be substantially shielded from the radiation from the gases of combustion thereof.

' 7. A vapor generator comprising a setting having opposite side and end walls, one of said side walls having a portion extending outwardly thereof in a verticallyinclined direction, vapor generating tubes in the setting, a furnace chamber within said walls, a radiant superheater disposed adjacent and substantially parallel to said outwardly extending portion of the sidewall, means for firing said furnace comprising burners in one end wall of said setting adapted to direct a stream of gases of combustion toward the other end wall, at least one of said burners being so disposed that heat from the gases of combustion thereof is radiated directly to the radiant superheaten-and another burner positioned at a higher elevation than the first menceive steam from the steam generating tubes, a

burner for firing the furnace chamber so disposed that heat from the gases of combustion thereof is radiated directly into the offset portion, and another burner so positioned that the ingopposite side and end walls, steam generating tubes in the setting, a furnace chamber within said walls, a hopper bottom associated with the furnace comprising opposite walls inclined inwardly, side Wall portions inclined oppositely to I said hopper bottom walls and extending between the upper portion of the hopper bottom walls and the lower portion of the first-mentioned side walls, radiant superheaters extending along the said side wall portions, separately controlled burners in one end wall of the settihg adapted to direct a stream of gases of combustion toward the opposite end wall, at least one of said burners being so disposed that heat from the gases of combustion thereof is radiated directly to the radiant superheaters, and another burner so p0 sitioned that the radiant superheaters are substantially shielded from radiations from the gases of combustion thereof.

6. A Vapor generator comprising a setting, vapor generating tubes in the setting, a furnace tioned burner and at a-lower elevation than said outlet, said other burner being disposed to fire in such a direction that the gases in flowing to portion thereof, said chamber having a laterally offset portion therein with a wall vertically in clined outwardly from the chamber, a radiant superheater in said offset portion adjacent and substantially parallel to the inclined wall thereof, a hopper bottom associated with the furnace comprising opposite walls inclined outwardly toward the chamber, a burner for firing the furnace chamber so disposed that heat from the gases of combustion thereof is radiated directly into the offset portion, and another burner positioned at a higher elevation than the first mentioned burner and at a lower elevation than said outlet, said other burner being disposed to fire in such a direction that the gases in flowing to cERTIFi GATE OF CORRECTION.

Patent No. 2,567,195. January 16, 191$.

JOHN BLIZARD.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, second column, line 50, claim-8, for the word "outwardly" read -inward1y--;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of M A, D, 1915,

Leslie Frazer (Seal) Acting Commissioner of Patents. 

